ferngren



1927. June 74 E. T, FERNGRr-:N

METHOD AND APPARATUS. FOR PRODUCING SHEET GLASS June 7 1927. 1,631,804

y E. T. FERNGREN METHOD AND APPARATUS FOR PRQDUCING SHEET GLASS Filed Aug. 21. 1922 s sheets-'sheet 5 [lll Patented June 7, 1927.

PATENT OFFICE.

UNITED STATES ENOCH T. FERNGREN, OF TOLEDO, OHIO, ASSIGNOR TO THE LIBBEYOWENS SHEET GLASS COMlEANY, OF TOLEDO, OHIO, .A CORPORATION OF OHIO.

METHOD AND APPARATUS FOR PRODU'CING:` SHEET GLASS.

Application tiled August 21, 1922.

lThis invention relates to the art of prod ucing sheet glass, and more particularly to an improved met-hed and apparatus for drawing a sheet of glass downwardly through a. slot or `orifice in the bottom of a receptacle containing the supply of molten glass.

The invention embodies a, method and means for regulating the fiow of molten glass to the slot.; for decreasing the glass contacting surfaces of the refractory mem bers adjacent the overflow passages at the slot; and for creating a live tensional resistance in the surface glassabove the slot, to resist the drawing action and support the sheet from above, independently of the overiiow surfaces at the slot sides.

Other objects and advantages of the in vention will be apparent from the following detailed description of certain forms of apparatus adapted to carry out the principles of the invention.

In the accompanying drawings:

Fig. 1 is a perspective view, partly in ver tical transverse section, of the preferred form of the apparatus. Y

Fig. 2 is a plan view of the structure shown in Fig. 1, with the roof rcmoved.`

Fig. 3 is an end View of the parts shown in Fig. 2.

Fig. i is a partial section similar to Figgl, showing a somewhat modified form of sheetsupporting and iloiv-i'egt1lati1ig member.

Fig. 5 is a view similar to Fig. 1, of a modified form'of apparat-usgthe cover portions or roof for the receptacle and tank being removed. 1

F ig. 6 is a perspective view of a form of dow-regulating member', and

Fig. 7 is an end view of this'member.

Referring first to Figs. 1, 2 and 3, the supply of molten glass 1 in receptacle 2 is in. open communication with a continuous tank furnace 3 or other suitable source of molten glass, whereby the supply of molten glass 1 may be continually replenished.

The bottom of receptacle 2 has a slot or orifice at 4, through which the molten glass may escape or be drawn away in sheet form as indicated at 5. The slot or orifice t is formed between the upwardly projecting lip portions 6 ofthe two refractorytiles 7 and 8. It should be noted that the'highest points of the two upwardly slanting ridge portions of the tiles curve over into the slot so as to' Serial No. 583,346.

give a minimum of frictional and clinging surface to the molten glass as it flows or is drawn into the sheet. The upwardly slanting tiles also provide a much shallower over flow passage for the glass at either side of the slot, thus accelerating the rate of flow at this point, so that the glass will not linger in contact with the lips 6, and freeze or adhere ther-cto. The side walls of these passages are tapered in as at 9 (Fig. 2) to direct the How of glass to the slot, and prevent stagnation near the ends thereof.

An inverted cap or closure member 10 of refractory material is mounted above, and straddling, the slot 4, with its downwardly extending side walls 11 and end walls 12 projecting into the pool of molten glass 1.

It will be noted that the side walls 11 are thicker at their central portions 13 than at the ends 14.-. The greater bulk or crosssection at the center offers a greater resistance to the flow of the molten glass. As the flow will ordinarily be freer and faster at `the center than at the ends, this added resistance or obstacle to the iiow at-the center tends toequalize the iiow throughout the length of the slot. Different variations of form are given to these flow resisting members in Figs. 5, 6 and 7; the walls being curved downwardly at their centers in Fig. 5, `and beingv thicker in both height and breadth in Figs. 6 and 7. The object in any case is to offer a greater resistance to the flow of the glass at the center, either by impeding its Vliirogress by narrowing the assage, or by voffering a greater surface o refractory material to which the glass will tend to cling. By equalizing the flow throughout the length of the slot, the sheet will be drawn oif evenly and will not tend to run ahead at the center, under the influ ence of gravity.

The walls 11 and 12 of the closure member 10, partially cut oif or isolate the body of molten glass above the slot l from the .main body of glass 1. The glass thus partly shut ofi' from the main body will have its level lowered as the sheet of glass is drawn therefrom. A partial vacuum will be thus formed above this glass so that the air pressure acting up through the slot 4 from be low will tend to support the sheet source, and relieve the supporting strain on the lips 6. At the same time there will be a movement of glass from outside the closure member l1Q,und,er the side walls,` 11, to replace the glass being pulled down through the slotV 4t. The upwardly pushing indo-wing glass` will tend to raise the glass level withinjthew member 10,'.nearf'tii' Siae-weils 11i est 15j, while the outflowing glass tends to`lovver the level at the centerl.' As these actions-,are in opposition to one another, the surface of the enclosed mol-ten glass! isconstantly being tensioned more than normal. This willcreate alive trlactiveforce tending to resist' the drawingaction` and 'si11`opoi't3`-tl1e sheet siirce." 'l

" To aid 'inthe above actions, the air may be partially-'ehausted V'from 'the space above fthe enclosed glass to increase the vacuum.

vFor this np uip'os'ea pipe17 is indicated in Fig. ljpifojecting in; through theyfmolten `glass which' acts as'aseal".` This 'pipe may `be connected with any suitable airl'exghaust-l I. ing apparatus.

In the modification shown in AFig-f1, the

closure"1nember 18has,"in` addition to the side walls 19, acentral downi'vardly projecta ingw'all: or flange 20. v rllhis projects into'the molte'n glass directly above theshect source,`

andthe adherence of theglass' thereto serves as any additional supportingmeans ior the sheet'."

"In the modiiicatyion shown lin Fig. 5, the sheet-supp'orting'A and flowresisting member 21 differs" 'from fthe ymemibers 10. yandl 18l already described, lin having the central opening22 open at:1 the` top. rIhefside fwallsQ- similar tol'a'pairj otfloaters. joincdxat theiifeiidsffasat Qllf The actionlotthisform forms l already described, exceptv 'the' vacuum feature 'is absent. The float willact as a re-v sistor to fthe drawing actiom'fiirsh reason of the large glass engaging andiclmging suringtoward the" orilice, and secondbyf. reason offthfe'surface tension` on the.. glass within the lcentraliopening 22A of the float.y

As already7Jv` mentioned, lthis 'memberzQl die asfishown at 25, 5.)', .or these walls may be both-'deeper as shownfat 26. and :wider las shown'at 27,"Figsi 6 andf. In anycase these'thicker portions act as a greater; dragVA on the glass at these points andtendllto equal-r glass to'all parts of.

iZe-the flow of molten theoric'elor' slot 4.' v l v The positin or'height-lofthe members 10, 18 'or 21,' within' .the molten glass may be regulated for adjsted byinserting'or remov-4 'ing sh'ims 28,0111 which thezmemberv rests at` its 'endsiy Inl order to .entirely cut; oft'ithe flow ofg'l'assto the slot r orifice when; it is ydesired to Edisc'ontinuethe; sheet.-dra..'11,g,lf,` operatiom'lthe members.10;01 18.1mafyfbe low-y ered into 'contact with the bottomtles 1.7. and

8 of thecohta-ining receptacle l2. In. Figi 5,

a cut-ol gate 29 fis indicated in .dottedlines 'ing roller` 31, andl carriedgavvay in1 the horizontal plane, buftit is to be.` understood that the sheet may be'Y drawnaway, flattened, annealed, land severed into sectionsr eitheriin the verticalfor horizontal planes, andfby.` any suitable mechanism for these purposes,`

4It"will be notedl thatgwith.anapparatus of ythisitype, the glass sheet will be `under al conetant;v retractive, stress while beingdrawn. downwardly through the slot `or; orifice, which stress or supportingE forcerelieves the lips at theedges 'ofthe slot ot a large part of the drawinglstress, sov that the-'glass may be maintained hotter` and morel fluid `where it passesovcr the lips and have.lessttendency to stick theretoy and; form lines-.or other .blemisl'ies inthesheet surfaces. f The; draw# ing tension is connedlargely tothe interior portions ofythesheet, the surface portions ,be-` ina fornledf by'. mere. Qf; e fownaabfen- These surfaces shrink onto. thecoolerfmore tenacious interior, forming smooth fiat surfaces. i A

f Claims:

1. In the method. of producingsheet glass by ,moving the glass downwafrdlyr through an orifice yin y the yinolten-glass containen that step wherein the ksurfacef portion fof` the molten glass directly7 overlying thecritic-eds,V

isolated -fremthaman body. Ot'alassand an increased surface. tension.v is created lin this isolated section, byproviding. spaced f clinging sur-faces to which theedges of'theiisof latedbody @telas .may adhere..

'24, In'the methodoiplroducing sheet; glass by moving the glass downwardly `through ,an o rice` in .thev` molten-glass containeqthat i step wherein. the surface, portion` I of .theme1- ten l glass directly `overlying yriice` is iso? lated frem the .main bdv f fi glass` and mi increased surfaceV tension. is .created in` this isolatedfsetion, by, :creating a` vacp The methodpf drawingasheetof glass downwardly through:anopeningwhich con# sists in lisolatilig thesurface of :theglass in the Lopening,and.-thereabove, from which the `sinectis..dwaalt` and/keeping@ elassundr ftractve yStress..l during. :the f ,fanzine opera-` 4' 1111 A @ne alair-eelsV for. .proteine .Shea

\ glass,y a retzeptacle 4for?A the `molten glass vhavingfa slottediorifce in; its bottom, the bottom walls adjacent the ,slot slopingnpwardly to provide Shallowoverfiow paeeages to the Slot.

5. ln an apparatus 'tor producing' sheet ase, a. receptacle for the molten glass having a Slotted orifice in its bottom, the bottom Walle adjacent the slot sloping upn wardly and having rounded tapered upper edges, to provide shallonT overflow passages to the alot, with small glass engaging eurlaces.

6. In an apparatus `for producing sheet ,f3-lass, a receptacle for the molten glaeeI haviup; a slot or orifice in its bottom through which the glass is drawn tol produce the sheet, and a pair of flow-reetrictiiral members projecting`v into the molten glass Within the receptacle at either side ot the orifice.

7. ln an apparatus for producing sheet glass, a receptacle for the molten glass having a slot or orifice in ite bottom through which the glass ie drawn to produce the sheet, and a pair of flow-reetricting members projecting into the molten glass Within the receptacle at either side of the orifice, said members beiner so formed as to impede the fioiv more at the center of the orifice than adjacent the ends thereof.

8. In an apparatus for producing sheet glass, a receptacle for the molten glass having a slot or orifice in its bottom through which the glass is drawn to produce the sheet, and a pair of flovv-restricting members projecting into the molten glass Within the receptacle at either side of the orifice, said members having a greater flow-impeding cross-section at their center than at their ends.

9. In an apparatus for producing sheet glass, a receptacle for the molten glass having a slot or orifice in its bottom through `which the glass is drawn to lproduce the sheet, and aA pair ol.' ioaters projecting' into the Surface molten glass adjacent the slot sides, to regulate the flow to the orifice, and produce an increaeed surface tension above the orifice.

` 10. ln au ajiparatus -tor producing sheet glass, a receptacle 'For the molten glass having;r a slot or orifice in its bottom tliirough which the glass is drawn to produce the sheet, and an inverted cap-member Whose Sides project into the molten glass at the aides,l of the orice, to 'form an enclosed suc tion chamber above the molten glass above the orifice.

ll. In an apparat-ue for producinf.lr sheet glass, a receptacle for the molten glase havingF a elet or orifice in its bot-tom through which the glass is drawn to produce the sheet, and an inverted cap-member Whose sides project into the molten glass at the sides of the orifice, to form an enclosed suction chamber above the molten glass above the orifice, and means for partially exhaustinn' the air from the chamber.

12. .In an apparatus for producing sheet glass, a receptacle for the molten glass p'rovided with a slotted orifice in its bottom, the bottom Walle adj aoent the orifice extending upwardly to provide shallow overflow passages to the orifice, and glass movement controlling; members projecting` into the glass adjacent the orifice for equalizing the ve1ocity of' glass movement toward and along the extent oit the orifice.

Signed at Toledo, in the county of Lucas, and State of Ohio, this 18th day of August, 1922.

ENooH r. remmenN.` 

